I really like the non-aerosol Niagara. It comes in a linen or lavender scent. I use it when working with applique pieces or if I have to piee bias edges. It helps keep the fabric from stretching and makes stitching easier.
Mary Ellen's Best Press is wonderful but it is expensive and I find for the difference in the price that the Niagara works great - the fabric is stiffer (starchier).